The present invention relates to a winding technique of winding wires on an armature that is provided at a rotor of an electric motor.
Among electric motors, one has a rotor unit and a stator. The rotor unit is formed by providing an armature core and a commutator on a shaft. A permanent magnet is provided on the stator. An armature has the armature core that is shaped like a column as a whole. A plurality of core slots extending in a radial direction in this armature core are each formed so as to penetrate from one end to the other of the armature core. A coil is formed by winding a wire in each core slot.
In the case where the wire for forming a coil is thin in diameter, a flyer winding machine as disclosed in Japanese Patent Laid-open No. 2-74141 can wind a core in each core slot by rotating a pair of arms. However, if the flyer winding machine is to form an armature core on which the thick wire in diameter is wound, since the wire is twisted and the armature core is deformed due to tension of the wire, it is difficult for the flyer winding machine to wind the thick coil in diameter.
In order to form a coil by using a thick wire in diameter, such a winding machine has been used that a wire is drawn out from a nozzle which is also called a capillary tube and which has the number corresponding to the number of core slots, and each nozzle reciprocates in an axial direction of the rotator unit to wind the coil in each core slot. This machine is also called a capillary type and is disclosed in, for example, Japanese Patent Laid-open No. 64-39248.
A pair of coils has straight portions and coil end portions. Each straight portion extends in an axial direction in two core slots between which the predetermined number of core slots is provided. The coil end portions are arranged along these straight portions and are also called crossover portions. Each one end of the pair of coils is installed at a predetermined engagement groove in the commutator, and the other end is installed at an engagement groove in a location spaced a predetermined pitch from the engagement groove at which the one end is installed.
In methods of forming the coil end portions by the capillary type winding machine, there are such a shaping-winding method as to form the coil end portions like a mountain shape or a square shape and such a direct-winding method as to form the coil end portions by directly winding a wire folded back.
The direct-winding method has no step of forming the coil end portions, so that it has an advantage over reduction of time required for winding the wire in comparison with the shaping-winding method. However, in this method, since crossover portions to be formed as coil end portions are piled up at an end surface of the armature, the number of coils wound in coil slots can not be increased. Therefore, even if a sectional area of the coil slot have a space enough to enter the coils, the number of coils is restricted.
Over against this, the shaping-winding method has can increase the winding number of coils inserted into the coil slot and improve an occupancy rate of the coils therein by isolating the coil end portions from the end surface of the armature core. However, in this method, a forming step is required and time for winding is required in comparison with the direct-winding method, so that efficiency of manufacture is decreased.
On the other hand, in the case where a capillary type winding machine draws out the wire from each nozzle to each core slot and simultaneously winds the wire even if either the shaping-winding or the direct-winding method is used, an overlap shape of the coil end portions becomes a twist shape. Therefore, such a dimension increases as to project from both end surfaces located in an axial direction of the armature core in a coil terminal portion formed by all the coil end portions. Even if each sectional area of the core slot is enlarged to increase the winding number of coils, the winding number is restricted by the projection dimension of the coil terminal portion. And, even if each core slot has a occupancy rate enough for each cross-section of the coils occupied therein, the winding number of coils can not be increased.
Further, if each shape of the coil end portions becomes twisted, it is impossible to use effectively a winding space of the end surface of the armature core in the case where a shaft has a thin radius because the minimum winding radius is determined by overlaps of the coil end portions.
An object of the present invention is to provide a winding method of an armature, which can manufacture efficiently the armature even if the winding number of coils wound in core slots is increased.
Another object of the invention is to provide a winding method of an armature, which can manufacture the armature in which a projecting dimension of each coil end portion formed at an end surface of an armature core is small even if the winding number of coils wound in core slots is increased.
Still another object of the invention is to provide a winding apparatus of an armature core, which can form coil end portions even if either a shaping-winding or direct-winding method is used.
According to a winding method of an armature that is the present invention, a winding method of an armature winding a coil by drawing out a wire from a plurality of nozzles, on an armature core which is provided on a shaft and on which a plurality of core slots extend in an axial direction thereof and is radiately formed, said winding method comprises the steps of: moving each of said nozzles from one end side of said armature core to the other end side, and inserting the wire into a first core slot; moving each of said nozzles from the other end side of said armature back to the one end side, and inserting the wire into a second core slot different from said first core slot; forming a coil end portion by bending a crossover portion which is formed in both sides of an end surface of said armature core and connects each wire existing in said first and second core slots; and making said nozzles close to said shaft, and thereby pressing said crossover portion on said shaft.
Further, according to a winding method of an armature that is the present invention, a winding method of an armature winding a coil by drawing out a wire from a plurality of nozzles, on an armature core which is provided on a shaft and on which a plurality of core slots extend in an axial direction thereof and is radiately formed, said winding method comprises the steps of: moving each of said nozzles from one end side of said armature core to the other end side, and inserting the wire into a first core slot; moving each of said nozzles from the other end side of said armature back to the one end side, and inserting the wire into a second core slot different from said first core slot; and forming a coil end portion by bending a crossover portion which is formed in both sides of an end surface of said armature core and connects each wire existing in said first and second core slots, wherein, in order to form a predetermined winding number of coils in said armature core, a plurality of coil end portions formed by repeating plural numbers each of said steps from a first time to a last time are closer to the end surface of said armature core as the number of times increases from the first time to the last time.
According to a winding method of an armature that is the present invention, a winding method of an armature winding a coil by drawing out a wire from a plurality of nozzles, on an armature core which is provided on a shaft and on which a plurality of core slots extend in an axial direction thereof and is radiately formed, said winding method comprises the steps of: moving each of said nozzles from one end side of said armature core to the other end side, and inserting the wire into a first core slot; moving each of said nozzles from the other end side of said armature back to the one end side, and inserting the wire into a second core slot different from said first core slot; and forming a coil end portion by bending a crossover portion which is formed in both sides of an end surface of said armature core and connects each wire existing in said first and second core slots, wherein said coil end portion is formed during formation of a first to a predetermined number-th coils, and the wire is directly inserted into said first and second core slots without forming said coil end portion after said predetermined number-th coil is formed. In the winding method of an armature that is the present invention, a winding method of an armature further comprises a step of pressing, to the shaft, said coil end portion formed by forming said predetermined number-th coil.
According to a winding apparatus of an armature that is the present invention, a winding apparatus of an armature winding a coil by drawing out a wire from a plurality of nozzles, on an armature core which is provided on a shaft and on which a plurality of core slots extend in an axial direction thereof and is radiately formed, said winding apparatus comprises: a first collet chuck located to have the same center as a rotary center axis of said shaft, and holding one end portion of said shaft; a second collet chuck located to have the same center as said first collet chuck, and holding the other end portion of said shaft; a nozzle supporting member on which said nozzles are provided movably toward said rotary center axis and which is capable of reciprocating relatively in a direction lying along said rotary center axis and rotating relatively around said rotary center axis as a rotary center; a first coil end shaping means having a shaping hook which is provided reciprocatably outside said first collet chuck in a direction lying along said rotary center axis and forms a coil end portion in a side of one end surface of said armature; and a second coil end shaping means having a shaping hook which is provided reciprocatably outside said second collet chuck in a direction lying along said rotary center axis and forms a coil end portion in a side of the other end surface of said armature, wherein a crossover portion is pressed on said shaft by making said nozzles close to said shaft, said crossover portion connecting the wire inserted into a first core slot by moving each of said nozzles from one end side of said armature core to the other end side and the wire inserted into a second core slot different from said first core slot by moving each of said nozzles from the other end side of said armature back to one end side. According to the winding apparatus of an armature that is the present invention, in order to form a predetermined winding number of coils on said armature core, a plurality of coil end portions formed by repeating plural numbers a reciprocation of said nozzles in a direction lying along said rotary center axis are closer to an end surface of said armature core as the forming number of the coil end potions.increases from a first time to a last time.
According to the present invention, coil end portions enter a step portion between an outer surface of a shaft and a bottom surface of each of core slots outside both end surfaces of an armature core, so that a space for winding coils at the end portion of the armature core can be effectively used. Further, each length of the coil end portions projecting from the end surface of the armature core gradually becomes short as each coil end portion moves from the vicinity of the shaft to the outside of a radius direction, so that the coil terminal portion formed by all the coil end portions can be miniaturized in size even if the winding number of coils is increased.
According to the present invention, a shaping-winding method for forming the coil end portions is operated between the first winding and the predetermined number-th winding. A direct-winding method for forming the coil end portions is operated between the predetermined number-th winding and the last winding. Therefore, in comparison with the case where all the coil end portions are formed by the shaping-winding method, it is possible to reduce time required for winding the coils and to improve efficiency for manufacturing the armature. Since the shaping-winding method is executed between the first winding and the predetermined number-th winding, it is possible to increase the winding numbers in each core slot without enlarging each coil end portion.